Marine Red Staining of a Pennsylvanian Carbonate Slope: Environmental and Oceanographic Significance

Red-stained platform facies are a common feature of many carbonate settings throughout the geological record. Although the mechanisms involved in red staining of subaerially exposed or argillaceous, peri-platforin limestones are reasonably well understood, the environmental and oceanographic significance of red carbonates often remains uncertain. Here, sedimentological, sequence stratigraphic, geochemical, paleontological, and quantitative bathymetric data from Pennsylvanian red intervals across a well exposed carbonate platform top and slope are documented and interpreted in a process-oriented context. On the upper slope (80-350 meters below the shelf break), red intervals alternate with gray, mainly microbial algal boundstones. On the lower slope (350-600 meters below the shelf break), redeposited red-stained mud builds matrix-supported breccia tongues interbedded with predominantly redeposited, clast-supported carbonate debris. The presence of large volumes of fibrous calcite biocementstones as well as firingrounds point to low sedimentation rates or omission. In terms of sequence stratigraphy, red intervals occur within maximum flooding intervals and reflect near platform drowning. Elevated δ